Sleeve for indirectly heated cathode having an integral tab



s p 30, 5 R. FRIEDLI, JR 2,612,619

' SLEEVE FOR INDIRECTLY HEATED CATHODE HAVING AN INTEGRAL TAB Filed Nov. so, 1948 INVENTOR ORNEY ROBERT FRIEDLI,J R.

Patented Sept. 30, 1952 i UNITED STATE SLEEVE FOR INDIRECTLY HEATED CATH- 1 ODE HAVING'AN INTEGRAL TAB Robert Friedli, Jr., Irvingtcn, N. 3., assignor to Radio Corporation of America, a corporation of Delaware Application November 8 Claims.

The present invention relates to cathodes for electron discharge devices, and more particularly to a cathode sleeve having an integral tab for connection to a lead-in, and method-of making thesame. Cathode sleeves having integral tabs have heretofore been made by stamping a sheet metal "stock to provide a planar form ofpredetermined -outlineusually taking the shape of a main rectangular body with a tab extending. from one edge thereof. The entire'form including the tab -:is then shaped on a mandrel which may be cylindrical, to providea cylindrical sleeve with a tab extending from .one end thereof. length of the tab is also caused to conform to 'theshape of the mandrel, resulting in a curvature therein in a transverse plane and an alignment of the tab with a longitudinal portion of .the sleeve. In some instances, the sleeve is also .provided with a bead adjacent the endthereof remote from the tab. The tab is usually longer than the spacing of the bead from the adjacent end of the sleeve. l Several problems are encountered in the handling and ultimate utilization in an electron discharge device of a cathode sleeve having a bead and an integral tab characterized by a transverse curvature'throughout its length. For'example, modern sleevemaking machines are relatively fast in operation and consequently require a means for rapidly removingcompleted cathode sleeves therefrom. One means found suitable and generally used comprises an'elongated man- 30, 1948, Serial No. 62,734

The entire .is curved transversely throughout its length, the engagement between the lead-invvire and the inwardly curved side of the tab is engaged byextension of the tab from the sleeve, attempts heretofore made to deflect the tab laterally have proven impractical due to prohibitive costs. in

adapting a sleeve making machine for thispurpose. It has been deemed more economlcalin prior practices to resort to; manual handling of each sleeve as itcomes'irom the machine than to modify existing machines...-

Another problem arlseswhen a having a transverselycurved tab is connected to its associated lead-in. The operation of connecting alead-in tothe cathode tab usuallyinvolves disposing an end portion of the lead-in wire transversely with respect to the tab and fixing the connection as by Welding. 'When the tab tab is tangential when the outwardly curved side of the tab isengaged by'the lead-in. When the I the lead-in only the longitudinal edges ofthe drel on which the finished sleeves are threaded intandem and along which they slide to a suitable receptacle. The cathode sleeves are fed to the elongated mandrel in such manner that the beaded end of one sleeve is in butt relation to the tabbed end of an adjacent sleeve. Where the tab is in alignment with the sleeve" and has a transverse curvature. throughout its length, the tab on one sleeve will engage the head on the adjacent-sleeve prior to butt engagement of adjacent ends of the sleeve proper. Since the transverse curvature of the tab at its free end isthe .sameas that of the sleeve and the bead, the entire free end of thetab will .butt against the'bead. This results in impedance to further travel of one sleeve with respect to the other on the, elongated mandrel and usually causes a buckling or collapse of the tab. Such collapse of the tab necessitates a manual straightening operation which requires a slowing down of the sleeve making machine and tedious and tiring work of one or more operators. The endresult of the tab engage the lead-in; As a consequence of the curvature in the tab therefore, only a rela-'- tively small surface engagement is possiblebetween the tab and the lead-inres'ultingin a'rela tively weak connection and possible electrical disturbances due to "the restricted electrical path provided by such weak connection. v

It is, therefore the object} of the invention to provide'an integrally tabbed cathode sleeve capable of delivery from a cathode sleeve making maczhiiie at a relatively fast rate and adaptedior good connection to a leadin, and a'method for making such sleeve. 1

A further object is to provide a cathode having an integral tab atlone end and a bead adjacent the other end wherein. butt relation between two sleeves is permitted Without a collapse of the tab.

Another object is to provide a cathode sleeve having a peripheral or annular bead adjacent one end and an integral tab extending from the other end and capable of tandem travel with like sleeves on a mandrel without a collapse of the tab.

A furtherobject is to provide a cathode-sleeve having an annular bead spaced a predetermined distance from one end thereof andanzintegral tab at the other end-extending therefroma'distance greater than said predetermined 'distance,

cathode sleeve the tab having a structure enabling a butt relation of two sleeves without collapse of the tab.

Another object is to provide an integral tab at one end of a sleeve-type cathode and a bead at the other end thereof spaced from said end by a distance less than the length of said tab, said tabbeing laterally deflected to clear the end of an adjacent sleeve and capable of further lateral deflection by the bead of an adjacent aligned sleeve to permit butt end engagement of two sleeves without collapse of the tab. Another object is to provide an integral tab on a cathode sleeve having a surface permitting good connection to a lead-in.

An additional object is to provide an integral tab on a cathode sleeve which has a curvature throughout a portion of its length .and which is fiat throughout another portion of its length, said last named portion extending to the end of the tab and providing a relatively small contact area at the free end thereof for engaging the head on an adjacent sleeve for lateral deflection ofthe tab, while providing a relatively large surface area for accomplishing a good mechanical and electrical connection to a lead-in.

further object is to provide a relatively simple and economical method for making a cathode sleeve and an integral tab wherein the endportion of the tab is substantially planar and is slightly deflected laterally from an end projection of the sleeve.

Another object is to provide a method for forming an integral cathode tab so as to have a rounded longitudinal portion and a flattened longitudinal portion automatically deflected laterally during the forming step; Further objects and advantages of the inventionwill become apparent as the description proc'eeds.

. '"In the drawing to which reference is now made for a better understanding of the invention, several. embodiments of the invention are presented by way of illustration only and not by way of limitation.-

' Figure 1 shows an electron discharge device partly broken away, incorporating the novel cathode sleeve of the invention;

Figure 2 is a side elevation sleeve; 1 3 Figures 3 and 4 are, respectively, cross sections taken along the line 3-4 and 4-4 of Figure 2 and illustrate the transverse shapes or diflerent longitudinal portions or the integral tab on my novel cathode sleeve; 7

Fi ures -5, 6, 7 and :8 illustrate advantages of my cathode sleeve in being capable of rapid removal from a cathode sleeve making machine without collapse of the tab, Figure 5 showing a plurality of my novel sleeves threaded for travel in tandem on a mandrel, Figure 6 showing a stage .in'the feed of the sleeve in the mandrel in which the tab on one sleeve engages the bead on another sleeve prior to .butt engagement of the sleeves; Figure 7 illustrating the cross section of the tab at its point of engagement with the bead and indicating the relatively small surface engagement between the tab and the bead, and Figure 8 showing the substantially larger surface engagement resulting from the use of conventional cathode tabs of rounded cross section throughout their lengths which causes collapse of the tab;

' Figures 9, 10 and 11 illustrate my novel method, Figure 9 showing the flatstock from which my novel sleeve and integral tab are formed, Figure of my novel cathode end thereof to Motive means,

action imparted by a following sleeve.

cross section 33 10 indicating in cross section a side view of a tool I may employ in carrying out my method, and Figure 11 depicting a transverse section of Figure 10 along the lines l|--H and further illustrating my novel method; and

Figures 12, Band 1% .depictadvantages of my novel cathode sleeve in connecting it to a lead-in, Figure 12 showing the relatively large surface engagement permitted by my novel cathode tab with a lead-in, and Figures 12 and 14 showing the relativelysmall surface engagement permitted between the curved tab of the prior art and a lead-in.

Referring now in more detail to the drawing, there is shown in Figure 1 an electron discharge device having an envelope 20, a base 2| having contact prongs 22' and an electrode assembly including anode 23 and cathode 24 having an integral tab 25 connected ,to a lead-in 26.

According to the invention, and as more clearly shown in Figures 2,13 and 4, cathode '24. includes a sleeve '21 having an-integral tab ziwhich-in turn has'alongitudinal portion 28 curved transversely as shown in "Figure 4 to constitute a longitudinal projection of a portion of the end of sleeve 21, and another longitudinal portion 29 adjacent its free end having .a transverse section that is substantially rectangular .as shown in Figure 3 and slightly deflected laterally of the sleeve 2]. The sleeve :21 may also be provided with an annular or peripheral bead '30 adjacent its and remote from the tab 25. The head .30 is spaced from the adjacent end of sleeve 21 a sufiicient distance to permit'the adjacent. end, to protrude a short distance abovea spacer plate .31 shown in Figure 1 with the bead bearing against a surface of the plate. .In comparison with the spacing of bead 30 from the adjacent end of sleeve 21, the length of tab 25 is relatively large, for the reason that a relatively long tab is required for facilitating machine. ,In this arrangement the sleeves 21 are threaded on a mandrel 32' having :a shape conforming to the shape of the space defined. by the sleeve. This shape for example. may be cylindrical. The sleeves '21 are fed to mandrel 32 from the right-hand side and after traversing .the'mandrel the sleeves drop from the left-hand a suitable receptacle not shown. not shown, for, causing the sleeves to slide along the mandrel is applied to the sleeve initially placed on the mandrel at its right-hand end after the sleeve has been formed by a machine, not shown. eludes an elongated forming die, not shown, on which the sleeve is formed. Mandrel 32 may be placed in end relationship to such forming die .for receipt of finished sleeves therefrom. A sleeve initially threaded on mandrel 32 by said motive means is given further movement by a pushing To permit-of such pushing action the pushing sleeve and the sleeve being pushed are required to assume an abutting end relationship.

Heretofore this abutting end relationship of the sleeves has resulted in a buckling or collapse of the tab on one of the sleeves on engaging the bead30 on another sleeve. This is for the reason that such tabs have usually had a curved as shown in Figure 8 which is Such. machine usually in usually angularly similar to the transversecurva ture of the 'wall of sleeve 21. This results in a relatively large area of engagement between the end of tab 33-on one sleeve and the end 21 of an adjacentsleeve, which results in the'transmission of a relatively large force to the tab 33;

as a consequence of which-it buckles or collapses. Y

'In accordance with the inventiomhowever, as shown in Figure '7 the flattening of the end portion 29 of the tab 25 and a deflection laterally thereof results 'in' a clearance between the end 29 of the tab and the end of an adjacent sleeve and in addition provides a relatively small surface engagement between the end of tab 25 and the bead 30. This engagementfiiivolves sucha small surface that the tab responds in further lateral deflection to'the pushing action of the pushing sleeve whereby the tabis preserved against buckling or collapse.

Several reasons for this response of my novel tab are evident. When the tab 33 is rounded throughout its length the consequent increase in the area of engagement between the tab end and the. bead 30 results in .a relatively large magnitude of friction between: the two whichimparts anundesirable amount of force to the tab. My novel tabhaving a flat end portion involves less surface engagement and consequently less friction, as shown in Fig. '7. Again, the tab 33 is not easily deflectible laterally because of its curvature, the curvature imparting such a degree of resistance to lateral components of "force that the "curved tab resists deflection to a considerably greater degree than does the tab of the invention having the flattened end portion 29 as shown in Figure '7. Therefore, my novel tab responds in deflection to a force that is 'far less than that required to cause it to buckle whereas the rounded tab of the prior art-is inherently incapable of lateral deflection without considerable distortion of its shape resulting in buckling.

The initial deflection laterally of my novel tab results automatically from the method I employ in forming the sleeve. This method is illustrated in Figures 9, and 11. My novel sleeve is first stamped from sheet metal stock to form a planar body 36 having a rectangular portion 31 and a tab 38. This planar body is then. placed between two parts of a forming tool shown in Figures 10 and 11.

This forming tool includes a mandrel shaped anvil 39 and a pressing member 40. The pressing member 40 is provided with a critical length in relation to the overall length of the planar form 36, including the tab 38, so that it engages the full length of the rectangular portion 31, but only engages a part of the length of the tab 38. Pressing member 40 is provided with a sharp edge 4| at its end adjacent the tab 38. When the planar body 36 is placed between the mandrel 39 and the pressing member 40 and pressure is applied to the pressing member, a portion of the planar body as well as a portion of the tab is rounded as shown in Figure 11. The sharp edge M on the pressing member 40 performs two functions on engaging the tab 38. It serves to form a sharp transition area or step between the area of curvature imparted by the forming tool and the original planar form of the tab extending beyond the pressing member 40, and it also automatically results in a slight deflection of the flat uncurved end portion of the tab away from the surface of mandrel 39 due to a tensile force resulting from the formation of the s te'p referred to and applied to the top surfaceof the flat portion of the tab, having the effect of pulling said surface portion toward said step. The under face of the flat planar portion of the tab serves to retard this pulling action, and the combination of this retarding action with the pulling action referred to 'resultsin a'deflection laterally of the flattened portion of the tab from the mandrel 39, This slight deflection-'isusually sufficient to cause the free end of the tab to clear the end of an adjacent sleevetraveling on elon-' gated mandrel 32, although not usually sufficient to cause the tab to clear the bead 30 orian adjacent sleeve.

It will be appreciated therefore that my novel method of forming a cathode sleeve with an-integral tab results in an improved sleeve having a structure .that contributes appreciably to ease in manufacture. Thus my novel method provides'a cathode sleeve having" a novel integral tab that has many advantageous characteristics. For example, the slight lateral deflection offthe end portion of the tab contributes to ease in clearing the end portion of an adjacently disposed sleeve. Again, the flat end portion of the tab further contributes'to facility in clearance between the tab on a sleeve and the bead on an adjacent sleeve. According to my invention therefore the desirable'method of transporting cathode sleeves from a sleeve making machine to a receptacle by causing the sleeve to travel in tandem on the mandrel, in response to a pushing force, is permitted without the danger of buckling or collapse of the tab. I t

- After the sleeve has been partly formed in accordance with the method of my invention it may be completed by conventional methods to bring the two edges thereof 42 and 43 into engagement in any suitable manner such as by way of a lock seam, not shown.

Another respect in which my novel cathode sleeve is advantageous is illustrated in Figure 12 which is a section along i2--I2 of Figure 1 and which shows the improved connection to a lead-in that my novel tab permits.

Usually in order to make a connection between a cathode tab and a lead-in the two are disposed in transverse relationship. When this relationship is assumed in association with my novel tab, the flattened end portion of the tab affords a planar surface that is parallel to a longitudinal portion of a lead-in 26 as shown in Figure 12. This provides the maximum area of engagement between the lead-in and the tab, and a weld 34 therebetween constitutes a relatively large body for good mechanical and electrical connection. Figures 13 and 14 show deficient connections resulting from connecting a curved tab to a lead-in.

- displaced from the lead-in than the central portion thereof with the result that the weld will include only the central portion of the tab. If the lead-in is connected to the inwardly curved side of the tab, edge portions thereof will be closer to the lead-in than the central portion thereof, resulting in a weld of the edge portions only of the lead-in to the tag.

This advantage of my invention insuring a good connection between a lead-in and a cathode tab results solely from the structure of my tab comprising a flattened end portion thereof,

and is entirely unrelatedto the head 30. .As a consequencemy invention may be practiced utilizing a cathode sleeve without the head 30.

- Other advantages and embodiments of my invention will be readily apparent to persons skilledin the art. It is, therefore, desired that the invention be given a scope commensurate with the appended claims.

. What I claim is:

. 1.;A cathode sleeve having an integraltab, a portion. of said tab adjacent said sleeve followingthe curvature of said sleeve in cross section, and-another'portionof said tab adjacent the free endo'f said tab having a larger radius of curvature than said first mentioned portion and bei'ngsubstantially fiat. .A cathode sleeve having an integral tab, a portion of said tab adjacent said sleeve being curved in cross section, and another'portion ofsaid tab adjacent the free end of said tab being substantially rectangular in cross section, whereby said first-named portion has a greater curvature in cross section than the second-named Portion. I

3. A cathode sleeve having anintegral tab, the free end of said tab terminating in an edge having. substantially rectangular shape, a portion of said tab adjacent said sleeve having a cross section including two curved opposite sides.

4. A cathode sleeve having an integral tab, said tabincluding a portion adjacent said sleeve havi'ng'a curved cross section, and another portion adjacent its free end having a rectangular cross section and angularly disposed with respect to the axis of said curved cross section.

5. A cathode sleeve comprising a tubular portion and an integral tab extending from one end of said tubular portion, said tab having a curved cross section adjacent said tubular portion, said tab adjacent the free end thereof being fiat.

6. An electron discharge device including a tubular cathode. having an integral single thickness tab extending from one end thereof, said tab having a'curved cross section adjacent said tubular portion, a portion adjacent the free end of said tab being flat, a 1ead-inior said device. said lead-in being connected to the last-named portion of said tab.

7. A cathode sleeve comprising a tubular-portionand an integral tab extending from one end of said tubular portion, said tubular portion having an annular bead adjacent the other end thereof, said tab having a curved cross section adjacent said tubular portion, a portion of said tab adjacent the free end thereof being planar and deflected angularly with respect to the axis of said tubular portion. I

8. A cathode sleeve having an integral tab, the free end portion of said tablying in asingle plane and being angularly disposed with respect to the axis of said sleeve and terminating in an edge having substantially rectangular shape.

v 1 ROBERT FRIEDLI, JR.

REFERENCES CITED The following references are of record the file of this patent:

UNITED STATES PATENTS Green Dec. 

